import java.util.Scanner;

public class Test {

    public static void main(String[] args) {
        System.out.println("第一个月有一对兔子，请输入月份：");
        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        System.out.println("第" + n + "个月有" + Fib1(n) + "对兔子");
    }

    private static int Fib1(int n) {//递归
        if(n == 1 || n == 2){
            return 1;
        }else{
            int a = Fib1(n-1) + Fib1(n-2);
            return a;
        }
    }
}
